Mar. 28, 2013
|

A massive red tide stretches for more than 20 miles along the southern California coast. / NOAA

by Doyle Rice, USA TODAY

by Doyle Rice, USA TODAY

New England should see a "moderate" red tide this spring and summer, according a report released this week by the Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration. Some shellfish harvesting beds might have to be closed in order to prevent people from eating contaminated food and getting sick.

Red tide is the common name for a harmful form of microscopic algae that turns the ocean a rust color and accumulates in shellfish, which can be deadly to humans if eaten. Each spring, warming ocean water and sunlight cause the explosive growth in the Gulf of Maine, usually by the end of April.

"Red tide is a chronic problem throughout the Gulf of Maine, affecting commercial and recreational harvesting interests," said Chris Nash, shellfish program manager for the New Hampshire Department of Environmental Services.

Besides "moderate," the other categories are "limited" and "extensive," and refer to how much of the Gulf of Maine coast could be closed because of red tide.

New England's red tide algae contaminate clams, mussels and oysters - but not lobster, crabs, shrimp or fin fish. The shellfish that ingest the algae aren't harmed either, as they flush it out of their systems after the water clears.

However, people who eat the tainted shellfish can develop paralytic shellfish poisoning, which can cause nausea, vomiting, abdominal pain and tingling or burning sensations on the face and extremities. In extreme cases, death can result.

The worst red tide outbreak on record was in 2005, according to the Woods Hole Oceanographic Institution. That year, shellfish beds were shut down along the New England coast and cost about $50 million to the Massachusetts shellfish industry alone. Another bad outbreak was in 2008.

Red tide has also been in the news recently in Florida: In southwest Florida, a red tide lingering offshore since September has killed 184 manatees and also prompted beach closings. According to the Save the Manatee Club, the red tide algae give off a toxic byproduct that affects the central nervous system of manatees in the area of the bloom.

On the east coast of Florida, at least 55 manatees have died in the Indian River Lagoon since July, including 25 of them in the past month alone. Scientists aren't sure whether the deaths are related to red tide.